Found a program that comes with the GPS that gives info about it. I used it to turn on WAAS. Will do another run to see how it looks. The circle is the same size. The circle does not appear with tracking disabled.

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__________________Paul," One moment you are running along, the next you are no more." Dean Spanley

Yes I guess its the circle around the track. If I turn off track highlighting it disappears. This what it looks like now after a few hours with WAAS on and also I changed the OpenCPN Tracking Precision from low to high so it shows most of the track points.

Well Stu I think a lot of sailors would like to know how accurate their instruments are, but as you say it still should be just a guide.

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__________________Paul," One moment you are running along, the next you are no more." Dean Spanley

Well Stu I think a lot of sailors would like to know how accurate their instruments are, but as you say it still should be just a guide.

Paul,

When I first got my old Magellan Blazer 10 or 12 GPS, no charts, I watched it change the lat/lon every few seconds.

When I got my Garmin GPSMap 76 Cx maybe ten years ago, I watched my "location" jump around when I was in my slip. Gee, it still does! I did exactly what you're doing, by zooming way into "overzoom" on the chart.

What it taught me was never to use the GPS to get back to my slip in a complete whiteout.

They are just NOT that accurate, nor were they ever intended to be.

If you read a tad of history, for example, the old Loran C systems were actually much better at repeat-ability to get BACK to the same point than are old &/or more modern WAAS enabled GPSs.

Too many people think that, because of electronics, precision is enhanced. Nothing could be further from the truth for many reasons, reasons that folks have written entire books about.

That''s all I'm trying to say and it is the basics for navigation of ANY sort.

2. GNSS coupled with ground-referenced signals. For example, Yanmar has tested in Australia (and Japan, Taiwan, and the Philippines) its agricultural machinery using Japan's QZSS signals and a local ground-referenced signal. Yanmar reported that its agricultural machinery (tilling soil etc) had horizontal in-accuracy of few centimetres.

3. Land surveying equipment has for several years now used GNSS receivers, some (but not all) with ground-referenced signal reception, with much lower horizontal inaccuracy. Of course that gear is much more expensive than the gear available to recreational sailors. Next time you see a surveyor team, go chat and ask them for a Captain Cook at their gear.

Al

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“Fools say that you can only gain experience at your own expense, but I have always contrived to gain my experience at the expense of others.” - Otto von Bismarck